1. Field of the Invention
This invention relates to an apparatus for mounting an arrow rest with respect to an archery bow. More specifically, this invention relates to an apparatus for mounting an arrow rest with respect to an archery bow window, whereby the arrow rest moves in response to a movement of an archery arrow, usually in a downward direction away from the archery arrow, before a fletching of the archery arrow has an opportunity to contact the arrow rest.
2. Description of Related Art
In an archery bow, an archery arrow is usually suspended within a cutout in a bow riser and supported by an arrow rest. Many conventional apparatuses for mounting the arrow rest with respect to the archery bow allow the arrow rest to rotate or pivot, for example in a forward direction to avoid contact with the archery arrow after the archery arrow is released from the archery bow. Upon release of the archery arrow, the arrow rest may return to the original arrow loading position by applying a return bias force, for example a spring bias. The return bias force may be applied in a horizontal or vertical direction and may be adjusted to control a rate of return of the arrow rest to the original arrow loading position.
However, when an archery arrow is released from an archery bow having a conventional xe2x80x9cfall awayxe2x80x9d arrow rest, the arrow rest may return to the original position before the archery arrow passes the arrow rest due to an improperly adjusted return bias force, for example. Additionally, a fletching may contact a portion of the arrow rest during release of the archery arrow, which results in undesired deflection and/or misdirection of the archery arrow. Such deflection will cause an inaccurate shot, wherein the intended target is missed. Deflections may also cause undesired noise and archery arrow damage requiring premature replacement of archery arrow components.
Thus, there is an apparent need for an apparatus for mounting an arrow rest with respect to an archery bow which prevents a deflection and/or misdirection of an archery arrow after release of the archery arrow from the archery bow.
It is an object of this invention to provide an arrow rest to support an archery arrow which, upon release of the archery arrow, rotates or moves away from the archery arrow without interfering with or contacting a fletching or another component of the archery arrow.
It is another object of this invention to provide an arrow rest which, upon release of the archery arrow, is actuated to move away from the archery arrow, for example to prevent undesired deflection and/or misdirection of the released archery arrow.
It is another object of this invention to provide an arrow rest having an adjusting mechanism for varying or setting a force required to actuate the arrow rest to rotate from a first or arrow loading position to a second or actuated position.
It is yet another object of this invention to provide an arrow rest having a mechanism for adjusting a deflection or cushion distance which the arrow rest must travel before the arrow rest rotates or moves from the arrow loading position to the actuated position.
The above and other objects of this invention are accomplished with an apparatus for mounting an arrow rest with respect to an archery bow window which includes a housing, for example a bearing housing, mounted with respect to the archery bow window. The bearing housing may be rotatably positioned within a mounting bore formed by a support bracket. In one embodiment of this invention, the bearing housing is integrated with the support bracket. With the support bracket secured to the archery bow, a windage and an elevation of the arrow rest with respect to the support bracket can be adjusted by rotating the bearing housing within the mounting bore.
In one preferred embodiment of this invention, an arrow shaft support member is mounted with respect to the archery bow window. The arrow shaft support member moves in response to a movement of an archery arrow shaft. In one preferred embodiment of this invention, the arrow shaft support member may include a shaft rotatably positioned within a bore formed by the bearing housing and extending along the longitudinal axis of the apparatus. The shaft is rotatable between a first or arrow loading position and a second or actuated position. The arrow rest includes two prongs which support an archery arrow shaft in the arrow loading position. Preferably, each prong is connected to the shaft and rotatable with the shaft.
In one preferred embodiment of this invention, a cam is operatively connected to and operatively moveable or rotatable with the shaft. The cam forms a first cam surface having a variable profile along a length of the first cam surface. At least one boundary or transition surface is positioned or formed between the first cam surface and a periphery of the shaft and provides a transition or interference between the first cam surface and the periphery of shaft.
A first bias element, for example a compression spring, urges the follower toward the cam. A spring force adjustment means, for example an adjustment screw, is engageable with an aperture formed by the support bracket and contacts the first bias element. The adjustment screw may be rotated to urge the follower toward the first cam surface to adjust a bias force applied to the first cam surface by the follower. The bias force corresponds to a deflection or cushion force, which is a force required to deflect the prongs and disengage the follower from the first cam surface.
A second bias element, for example a torsion spring, is operatively connected to the shaft. The second bias element urges the shaft from the first position to the second position. A torsion spring force which is applied by the torsion spring to the shaft can be adjusted to affect the rate of rotation and acceleration of the shaft from the first position to the second position.
The archery bow can be set up to provide a slight downward component to a movement of the archery arrow after release of the archery arrow from the archery bow. The downward movement of the archery arrow urges the prongs forward in a downward rotational direction. As a result, the shaft is actuated to rotate from the first or arrow loading position to the second or actuated position. As the shaft rotates, the cam moves relative to the follower. As the follower contacts the transition surface, the second bias element provides a rotational torque to the shaft and the shaft rotates from the first position to the second position.
In one preferred embodiment of this invention, the shaft extends into a cavity formed by the bearing housing. The shaft forms a first interference surface and a second interference surface. A cam is operatively connected to the shaft. In one embodiment of this invention, the cam is rigidly connected to the shaft and rotates with the shaft. Alternatively, the cam may be pivotally connected to the shaft and may rotate relative to the shaft. Preferably, but not necessarily, the cam is pivotally connected to the shaft by a toggle bracket which is movable between a first toggle position and a second toggle position.
A follower contacts at least a portion of an exterior surface of the cam. A first bias element urges the follower toward the cam. A cushion force adjustment means, for example a first adjustment screw, moves or compresses the first bias element toward the follower to urge the follower toward the cam. Thus, a bias force applied to the cam by the follower is adjustable. The bias force initially maintains the shaft in the first position, wherein the prongs are positioned to accept and support an archery arrow. The bias force corresponds to a deflection or cushion force required to deflect the prongs. The toggle bracket correspondingly moves from the first toggle position to the second toggle position. A cushion distance adjustment means, for example a second adjustment screw, allows lateral adjustment of the follower with respect to the cam. Thus, an angle at which the follower applies the bias force to the cam, as well as a deflection or cushion distance of the follower, can be adjusted by rotating the second adjustment screw. The deflection or cushion distance defines a rotational distance, usually measured in degrees, which the arrow rest travels before it is actuated to move from the first position to the second position. This rotational distance corresponds to a distance which the cam must travel to move the toggle bracket from the first toggle position to the second toggle position.
The archery bow can be set up to provide a slight downward force component to the archery arrow after release of the archery arrow from the archery bow. The downward movement of the archery arrow urges the prongs forward in a downward rotational direction. As a result, the shaft moves from the first or arrow loading position to the second or actuated position. As the cam moves relative to the follower, a force vector of the first bias element causes the cam to accelerate toward the second toggle position.
Alternatively, if the archery arrow does not have a downward component to its movement, the arrow rest may be actuated to move from the first position to the second position by an inertial mass. The inertial mass remains stationary during the release of the archery arrow. As the arrow rest moves toward the stationary inertial mass during recoil of the archery bow, the cam is forced to move relative to the follower. Once the force vector of the follower relative to the cam moves from a counterclockwise direction to a clockwise direction, the arrow rest moves as described above.
In one preferred embodiment of this invention, the shaft is rotatably mounted within the bearing housing and at least a portion of the shaft extends into a cavity formed by the bearing housing. The shaft forms a first interference surface and a second interference surface, each extending radially from a longitudinal axis of the shaft.
A stirrup is mounted or connected to an end portion of the shaft which extends into the cavity. In one embodiment of this invention, the stirrup is rigidly connected to the shaft so that the stirrup rotates as the shaft rotates. Alternatively, the stirrup may be pivotally connected to the shaft to pivot independently of the shaft.
A bias element, for example an extension spring, is connected at a first end portion to the stirrup and at a second end portion to an adjustment block which is slidingly positioned within the bearing housing and moveable in at least one direction, for example in a generally vertical direction perpendicular to the longitudinal axis. With the shaft in the first position, the stirrup is moveable between a first toggle position wherein the stirrup contacts the first interference surface and a second toggle position wherein the stirrup contacts the second interference surface.
A cushion force adjustment means, for example a first adjustment screw, adjusts a distance between the adjustment block and the stirrup to apply a load force to the stirrup and initially maintain the shaft in the first position. The load force corresponds to a deflection or cushion force required to deflect the prongs and actuate the arrow rest.
A cushion distance adjustment means, for example a second adjustment screw, allows lateral adjustment of the second end portion of the bias element with respect to the first end portion of the bias element. An angle at which the bias element applies the load force to the stirrup, as well as a deflection or cushion distance of the bias element, can be adjusted by rotation of the second adjustment screw. The deflection or cushion distance relates to a distance which the stirrup must travel to move from the first toggle position to the second toggle position.
With the archery bow providing a slight downward component to a movement of the archery arrow after release of the archery arrow from the archery bow, the archery arrow urges the prongs forward in a downward direction. As a result, the stirrup moves from the first toggle position to the second toggle position, whereby the shaft rotates from the first position to the second position. As the stirrup moves relative to the second end portion of the bias element, a force vector of the bias element causes the stirrup to accelerate in a rotational direction. With the stirrup in the second toggle position, the shaft rotates until the shaft contacts a projection or stop pin formed into or connected to an inner surface of the bearing housing.
Alternatively, the arrow rest may be actuated to move from the first position to the second position by an inertial mass. If the archery arrow does not have a downward component to its movement, the inertial mass will remain stationary during the release of the archery arrow. During recoil of the archery bow toward the archer""s palm, the stirrup moves relative to the inertial mass. Because the arrow rest moves toward the stationary inertial mass, the stirrup is forced to move relative to the second end portion of the bias element. Once the force vector of the second end portion of the bias element relative to the stirrup moves from a counterclockwise direction to a clockwise direction, the arrow rest moves as described above.